The thesis explores priority setting in the National Health Service. It focuses on the changing way in which rationing issues are dealt with in the wake of the Health Service reforms and the separation of function between purchasing and providing health care. It examines how managers within sample District Health Authorities justify their priority-setting agenda. Two connected themes are also analysed. One is how health needs assessment and the call for a 'primary care led NHS' presage a more dominant role for Public Health medicine in informing purchasing. Secondly, how evidence based medicine together with the use of clinical protocols/guidelines, measurement of outcomes and the use of clinical/medical audit, become factors in the decision making process. Theoretically, the thesis attempts to demonstrate a practical use for the Foucauldian concept of 'governmentality' as a framework with which to analyse contemporary changes in health policy. The principal concern is the role experts play within the problematisation of government associated with liberalism. This includes their role within the institutions and technologies of governance that reflect the notion that the strength of the liberal state is derived from securing the well being of the population. In turn this reflects the self-critical dynamic within liberal problematisations of defining the legitimate boundaries of government responsibility in a society made up of autonomous individuals. The PhD is based on semi-structured interviews (32 in total), conducted with the Chief Executives and principal directors of six English District Health Authorities, together with the Chief Officers of their associated CHCs. The District Health Authorities were selected - after a general review of Health Authority Purchasing Plans for 1996/97 - from those Authorities that acknowledged the rationing debate in their purchasing intentions and represented a cross-section of gainers and losers with respect to the new funding formula.